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51.
An experimental investigation is conducted to obtain the heat transfer and pressure drop data for an integral trailing edge cavity test section that simulates a novel turbine blade's internal cooling passage with bleed holes. Local heat transfer is measured on both the suction and pressure sides by a transient liquid crystal technique, while pressures at six positions are recorded by pressure calibrators. Moreover, flow characteristic and its effect on heat transfer are analyzed for conditions with or without bleed flow. The experimental results show that, in the cases with bleed flow, local heat transfer on the pressure side exceeds that on the suction side in the first and second channels. In the cases without bleed flow, in the first and third channels, local heat transfer on the suction side weakens whilst it increases significantly on the pressure side. For the second channel, non-bleed condition leads to a more balanced heat transfer distribution between the upstream and downstream channel. Besides, after the bleed holes are blocked, heat transfer in the first bend region on the suction side declines sharply, while the opposite phenomenon occurs for the second bend region on the pressure side. In both bleed and non-bleed cases, the total pressure of six measurement positions decreases continuously along the channel at the same Reynolds number and it promotes for higher Reynolds number. Among all the measurement points, under the same flow rate condition, the highest speed occurs at Position 5, which also shows the maximum difference between the total and static pressures. When the bleed holes are blocked, the total pressure at each measurement position appears to increase. 相似文献
52.
R. Devaraj K. Sankarasubramanian Surekha Kamath 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Multi-slit spectropolarimeter is a next-generation spectropolarimeter to obtain vector magnetic field information at high spatial, spectral, and temporal resolution for studying the magnetic structures on the Sun. Once developed, it can be used as ground based instrument at solar observatories, also as a space payload for various solar missions. A high spectral resolution is invariably an important parameter for accurate vector magnetic field measurements and faster cadence is required for the study of dynamical evolution of structures (e.g., solar flares, sunspots etc.) on the Sun and hence better understanding on the physics behind their evolution. 相似文献
53.
通过使用MSC.Patran/Nastran中的p型有限元评价多种典型薄壁结构构件动力学品质分析中的特征值计算收敛问题,并对高阶形函数的作用进行了深入分析,从而说明高阶p型体元在薄壁结构建模中的优越性。 相似文献
54.
55.
LC4CS铝合金裂纹尖端腐蚀行为的实验研究 总被引:2,自引:2,他引:0
LC4CS铝合金是极为重要的航空材料,为评定其使用年限,在测定铝合金腐蚀疲劳裂纹的扩展速率时,需要弄清纹尖端金属的腐蚀电化学行为。在腐蚀环境中裂纹尖端由于不断露新鲜金属,因而将具有类似于双金属腐蚀时的电偶效应。为此,文中设计了一种新颖的缺口试样,再现裂纹尖端的真实状态,并在3.5%NaCl溶液测定剪切口断裂后,裸露出的新鲜金属在耦合前后腐蚀电位的变化,以及裸露面积,NaCl溶液的pH值与电偶电流的 相似文献
56.
57.
本文介绍了液态模锻工艺过程单片机仿真控制系统的设计方法,包括液态模锻工艺程确立、逻辑量确立、硬件系统设计、MDS图的建立及软件实现,在工艺设备的逻辑性控制中应用MDS图控制结构设计的控制器可方便方便地实现PLC的控制功能,也可主便地实现其他娄字逻辑系统的控制功能。 相似文献
58.
基于超塑性材料高温扩散蠕变、晶界滑移、孔洞闭合、界面再结晶机理,研究SPF/DB组合工艺的数值模拟,用非线性有限元数值模拟超塑成形和预测厚度变薄率,将有限元结果作为加载条件,计算扩散焊接焊合率和预测焊接强度,计算结果与3维实验数据曲面比较,吻合良好。 相似文献
59.
考虑了在外弹道测量中由于定位的测量误差(主要指常值误差)而带来的测速折射修正的误差。从折射修正的原理出发,推导了该项误差的表现形式。理论分析与仿真计算表明,在高准确度测量定轨中该项误差是不能忽略的。给出了扣除该误差的方法,以利于在数据处理中来消除该项误差,从而可提高定轨的准确度。 相似文献
60.
Coupled Lagrangian impingement spray model for doublet impinging injectors under liquid rocket engine operating conditions 总被引:2,自引:0,他引:2
To predict the effect of the liquid rocket engine combustion chamber conditions on the impingement spray, the conventional uncoupled spray model for impinging injectors is extended by considering the coupling of the jet impingement process and the ambient gas field. The new coupled model consists of the plain-orifice sub-model, the jet-jet impingement sub-model and the droplet collision sub-model. The parameters of the child droplet are determined with the jet-jet impingement sub-model using correlations about the liquid jet parameters and the chamber conditions.The overall model is benchmarked under various impingement angles, jet momentum and offcenter ratios. Agreement with the published experimental data validates the ability of the model to predict the key spray characteristics, such as the mass flux and mixture ratio distributions in quiescent air. Besides, impinging sprays under changing ambient pressure and non-uniform gas flow are investigated to explore the effect of liquid rocket engine chamber conditions. First, a transient impingement spray during engine start-up phase is simulated with prescribed pressure profile. The minimum average droplet diameter is achieved when the orifices work in cavitation state, and is about 30% smaller than the steady single phase state. Second, the effect of non-uniform gas flow produces off-center impingement and the rotated spray fan by 38°. The proposed model suggests more reasonable impingement spray characteristics than the uncoupled one and can be used as the first step in the complex simulation of coupling impingement spray and combustion in liquid rocket engines. 相似文献